From: Sean Christopherson <seanjc@xxxxxxxxxx>
Re-inject INTn software interrupts instead of retrying the instruction if
the CPU encountered an intercepted exception while vectoring the INTn,
e.g. if KVM intercepted a #PF when utilizing shadow paging. Retrying the
instruction is architecturally wrong e.g. will result in a spurious #DB
if there's a code breakpoint on the INT3/O, and lack of re-injection also
breaks nested virtualization, e.g. if L1 injects a software interrupt and
vectoring the injected interrupt encounters an exception that is
intercepted by L0 but not L1.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@xxxxxxxxxx>
---
arch/x86/kvm/svm/nested.c | 7 +++----
arch/x86/kvm/svm/svm.c | 23 +++++++++++++++++++----
2 files changed, 22 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 0163238aa198..a83e367ade54 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -617,10 +617,9 @@ static inline bool is_evtinj_soft(u32 evtinj)
if (!(evtinj & SVM_EVTINJ_VALID))
return false;
- /*
- * Intentionally return false for SOFT events, SVM doesn't yet support
- * re-injecting soft interrupts.
- */
+ if (type == SVM_EVTINJ_TYPE_SOFT)
+ return true;
+
return type == SVM_EVTINJ_TYPE_EXEPT && kvm_exception_is_soft(vector);
}
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 94d111ddec1c..a1158fc25c4c 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3430,12 +3430,22 @@ static void svm_inject_nmi(struct kvm_vcpu *vcpu)
static void svm_inject_irq(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
+ u32 type;
+
+ if (vcpu->arch.interrupt.soft) {
+ if (svm_update_soft_interrupt_rip(vcpu))
+ return;
+
+ type = SVM_EVTINJ_TYPE_SOFT;
+ } else {
+ type = SVM_EVTINJ_TYPE_INTR;
+ }
trace_kvm_inj_virq(vcpu->arch.interrupt.nr);
++vcpu->stat.irq_injections;
svm->vmcb->control.event_inj = vcpu->arch.interrupt.nr |
- SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_INTR;
+ SVM_EVTINJ_VALID | type;
}
void svm_complete_interrupt_delivery(struct kvm_vcpu *vcpu, int delivery_mode,
@@ -3715,6 +3725,8 @@ static inline void sync_lapic_to_cr8(struct kvm_vcpu *vcpu)
static void svm_complete_soft_interrupt(struct kvm_vcpu *vcpu, u8 vector,
int type)
{
+ bool is_exception = (type == SVM_EXITINTINFO_TYPE_EXEPT);
+ bool is_soft = (type == SVM_EXITINTINFO_TYPE_SOFT);
struct vcpu_svm *svm = to_svm(vcpu);
/*
@@ -3726,8 +3738,7 @@ static void svm_complete_soft_interrupt(struct kvm_vcpu *vcpu, u8 vector,
* the same event, i.e. if the event is a soft exception/interrupt,
* otherwise next_rip is unused on VMRUN.
*/
- if (nrips && type == SVM_EXITINTINFO_TYPE_EXEPT &&
- kvm_exception_is_soft(vector) &&
+ if (nrips && (is_soft || (is_exception && kvm_exception_is_soft(vector))) &&
kvm_is_linear_rip(vcpu, svm->soft_int_old_rip + svm->soft_int_csbase))
svm->vmcb->control.next_rip = svm->soft_int_next_rip;
/*
@@ -3738,7 +3749,7 @@ static void svm_complete_soft_interrupt(struct kvm_vcpu *vcpu, u8 vector,
* hit a #NP in the guest, and the #NP encountered a #PF, the #NP will
* be the reported vectored event, but RIP still needs to be unwound.
*/
- else if (!nrips && type == SVM_EXITINTINFO_TYPE_EXEPT &&
+ else if (!nrips && (is_soft || is_exception) &&
kvm_is_linear_rip(vcpu, svm->soft_int_next_rip + svm->soft_int_csbase))
kvm_rip_write(vcpu, svm->soft_int_old_rip);
}
@@ -3800,9 +3811,13 @@ static void svm_complete_interrupts(struct kvm_vcpu *vcpu)
case SVM_EXITINTINFO_TYPE_INTR:
kvm_queue_interrupt(vcpu, vector, false);
break;
+ case SVM_EXITINTINFO_TYPE_SOFT:
+ kvm_queue_interrupt(vcpu, vector, true);
+ break;
default:
break;
}
+
}
static void svm_cancel_injection(struct kvm_vcpu *vcpu)
